Element filled with phase-change material and production method

Abstract

The invention relates to a method for producing an element (300) at least partially filled with phase-change material, the method involving: providing a blank (100) which comprises a plurality of chambers (101-109) that extend from a first side (110) of the blank (100) to a second side (120) of the blank (100), are open on either side and comprise at least two first chambers (102-108) that are to be filled with a phase-change material; connecting the first chambers (102-108) by partially removing, on the side next to the first side (110) of the blank (100), the separating walls (130) extending between adjacent first chambers; closing the first chambers (102-108) towards the first side (110) of the blank (100); filling the first chambers from the second side (120) of the blank (100) with a phase-change material; and closing the first chambers towards the second side (120) of the blank (100), with the result that the first chambers (102-108) of the filled element (300) form mutually communicating cavities which are completely closed with respect to the surrounding area. The invention further relates to an element (300, 310) which is filled with phase-change material and can be produced in particular by the method.

Description

[0001] Element filled with phase change material and method for its manufacture

[0002] Description

[0003] The invention generally relates to an element at least partially filled with phase change material and to a method for producing an element at least partially filled with phase change material, wherein the element can be used in particular for thermal insulation or thermal stabilization and can be used, for example, for enclosing structures.

[0004] A latent heat storage device, also known as a phase-change storage device, is a special type of heat storage device that stores a large portion of the thermal energy supplied to it in the form of transition enthalpy, for example, during a phase change from solid to liquid. As long as the phase transition is not fully complete, the temperature of a substance does not rise further despite the addition of heat. Latent heat storage devices can therefore store very large amounts of heat in a narrow temperature range around the phase change, outperforming heat storage devices that only utilize the sensible thermal energy of a substance, such as hot water storage devices.

[0005] Since many substances with different melting points can be used as phase change materials or PGMs, this technology is used in various storage applications, such as ice packs or heat pads.

[0006] A latent storage material, or PCM, can be used as a storage medium for thermal stabilization because these materials melt at a defined temperature and absorb significant amounts of thermal energy during the melting process. A phase-change material can typically absorb up to approximately 80 kWh of energy per cubic meter without increasing the temperature of the object to be thermally stabilized with the phase-change material. For example, water, with a melting enthalpy of 333.5 J / kg, can be used as a phase-change material. However, various salts or organic compounds that change their state of aggregation under thermal loads and absorb thermal energy in the process are also used as storage media. Phase-change materials can be used for a variety of applications. For example, DE 10 2020 120 807 A1 describes a cooling battery using a phase-change material.A heat exchanger based on a phase-change material is described, for example, in WO 2010 / 092391 A1. Further examples of elements with phase-change materials are described in DE 100 58 101 A1 and DE 10 2016 109 825 A1.

[0007] From DE 10 2014 203 545 A1, a method for encapsulating a phase change material with a tubular casing is also known, in which in particular a hollow, rectilinear tube is closed on a first side, the tube is filled with a phase change material and, after filling, the second side of the tube is closed.

[0008] Latent heat storage devices predominantly use individual elements known as macroencapsulations, which can be shaped as cylinders, spheres, tetrahedrons, cuboids, or hybrids thereof. Changing the external shape of such macroencapsulations is complex, as a modified container shape typically requires a new deep-drawing or blow mold – the matrix into which the materials to be formed, such as plastic films or plastic fluids, are introduced to produce the containers. These molds must have extremely smooth walls and are associated with considerable manufacturing effort. Furthermore, such containers can only be scaled to a limited extent, as increasing the dimensions results in stability disadvantages. The surfaces are subjected to mechanical stress by the internal pressure of the latent storage material, causing them to bulge outwards, a process that can only be prevented with great effort.Due to the high cost of manufacturing large containers, resulting, for example, from complex designs in the blow mold, smaller containers are typically produced, which are then installed multiple times. A further disadvantage, especially when using large containers, is that in the event of an accident or breakage, almost the entire contents—that is, the phase-change material—are released, i.e., leak out.

[0009] The invention is based on the object of showing a way how a

[0010] A phase-change material-filled element can be provided in a simplified and / or improved manner. A further objective is to flexibly adapt such an element to different applications.

[0011] This object is achieved by the features of the independent claims. Advantageous embodiments are the subject of the dependent claims, wherein the stated features and advantages can essentially apply to all independent claims.

[0012] Accordingly, a method for producing an element at least partially filled with phase change material comprises the following steps: a) providing a blank having a plurality of chambers, wherein adjacent chambers are each separated from one another by a partition wall running between the adjacent chambers, wherein the chambers extend from a first side of the blank to a second side of the blank, the chambers are open towards the first and second sides of the blank, and the chambers comprise at least two first chambers to be filled with a phase change material, b) connecting the first chambers by partially removing the partition walls running between adjacent first chambers on the side facing the first side of the blank, c) closing the first chambers towards the first side of the blank while maintaining the connection of the first chambers,d) filling the first chambers with a phase change material by filling the phase change material into at least one of the first chambers from the second side of the blank, and e) closing the first chambers towards the second side of the blank, so that the first chambers of the filled element form communicating cavities that are completely closed to the environment.

[0013] The blank is preferably a semi-finished product, i.e. a prefabricated raw material or semi-finished product which has been given a basic geometric shape, in particular in the form of a predetermined profile. In other words, the blank is preferably a workpiece which has already been given an individual shape in a preparatory production step. The method offers further advantageous embodiments, in particular in connection with semi-finished products. For example, a change to the blank surface can be provided before, after and / or during the above-mentioned method steps, preferably in method steps c) and e), in particular to improve the blank surface with regard to at least one functional aspect. Thus, in step a), a blank with a correspondingly changed orimproved surface, the change in the surface can be integrated into at least one of the process steps, in particular into steps c) or e) for closing the blank, and / or the surface of the element closed on both sides can be subsequently changed.

[0014] In particular, it is advantageous to improve leak protection in the event of damage and fire protection by providing a non-combustible, close-meshed mesh structure and / or improving thermal conductivity through flocking, powder coating, or lamination of the surfaces. Furthermore, applying a mesh or grid structure to the surface of the element or panel can significantly improve the adhesion properties of surface finishes such as plaster or wallpaper. The functional aspects with respect to which the blank surface can preferably be improved thus include, in particular, leak protection, fire protection, thermal conductivity, and / or adhesion properties.

[0015] A mesh structure applied to the surface of the blank, whether before or after the above-mentioned process steps and / or integrated into them, offers particular advantages which are described below. The substance mixtures (PCMs) introduced as phase change materials are often rheologically adapted so that they have a yield point, i.e. they do not flow until a certain force is acted on them. Close-meshed structures can therefore advantageously prevent leakage. The leak protection achieved in this way functions similarly to the behavior of a paste that would flow slowly through a large funnel but remain on a fine-mesh sieve.Thus, a mesh structure offers additional leak protection beyond the mere segmentation of the total volume and rheological thickening, since, for example, an applied non-combustible mesh structure would remain intact in the event of a fire. A further advantage of a mesh structure is its interaction with the properties of inorganic mixtures of substances introduced as phase-change materials, particularly salt hydrates, in the event of a fire. In this case, the high temperatures inevitably cause rheological thickening to decrease, and the partition walls between adjacent chambers can also be destroyed. However, salt hydrates exhibit special properties that can have a fire-retardant effect, as they form inorganic, non-combustible crusts when the water content in the mixture evaporates.Initial tests by the inventors have shown that a mesh structure temporarily delays the phase-change material filling from falling while the structure is being damaged by a fire. This allows the water content to evaporate on site, forming a protective crust before the filling flows out of the flame radius.

[0016] In addition to the improved function achievable by the mesh structures described above, an improvement in temperature distribution can also be advantageously achieved, whereby the thermal performance of the elements, in addition to the thermal storage capacity, is another important criterion in the application. For this purpose, metallic paints, powders, laminates of thermally conductive films and / or grid structures can advantageously be provided, which can preferably be applied to the surface of the blank before, after and / or during the above-mentioned process steps or can be attached to the surface of the blank. This preferably takes place in steps c) and / or e), since there each semi-finished product is preferably processed with a constant and controlled feed.The improvement achievable in this way can be due to an increase in the thermal conductivity (“lambda”) along the element or into the element, an increase in the available surface area per container volume (m. 2 / m 3 ), or a combination thereof.

[0017] Advantageously, the blank is a semi-finished plastic product, in particular a plastic profile produced by forming, in particular by extrusion. Accordingly, the blank provided in step a) is preferably produced by an extrusion process, in particular by extrusion of a thermoplastic or thermosetting plastic.

[0018] The chambers of the blank preferably extend substantially parallel to one another along an axis from the first to the second side of the blank, wherein the blank is designed in particular as a hollow chamber plate, web plate, double web plate or multiple web plate.

[0019] Multi-wall sheets consist of large-surface sheets connected to one another by webs, creating cavities or hollow chambers inside that are separated from one another by the webs running between adjacent chambers. When a multi-wall sheet is used as a blank, the partition walls are thus formed by the webs of the multi-wall sheet. The chambers of the multi-wall sheet extend in particular from a first side of the multi-wall sheet to a second side of the multi-wall sheet. In the simplest case, the webs of multi-wall sheets run vertically between the sheets, forming chambers with a rectangular cross-sectional profile. Multi-wall sheets can be stiffened inside by additional webs, for example, arranged diagonally.

[0020] What is essential for the process is that the chambers extend from a first side of the blank to a second side of the blank and that the chambers are open to the first and second sides of the blank.

[0021] Hollow-core panels are also referred to as structural-core panels, such as dimpled-structured panels, which have cavities arranged between two panels, but do not extend from a first side to a second side and are open to both the first and second sides. Such structural-core panels are therefore not typically used.

[0022] The chambers of the blank provided in step a) comprise at least two first chambers that are filled with a phase change material. The blank can advantageously comprise a plurality of first chambers that are filled with a phase change material, in particular more than 10, in particular more than 20, in particular more than 50, in particular more than 80. In addition to the chambers referred to as first chambers, the blank can advantageously comprise further chambers that are not filled with a phase change material or that are filled with a different phase change material than the first chambers. Chambers that are not filled can, in particular, remain unsealed. Accordingly, the chambers advantageously comprise second chambers that are filled with a different material than the first chambers, in particular with air or water, and / or third chambers that are not sealed to the first and / or second side of the blank.

[0023] The filling of the first chambers with a phase change material is carried out by the steps b) to e) described above.

[0024] In step b), the first chambers are connected to one another by partially removing the partition walls running between adjacent first chambers on the side facing the first side of the blank. The removal can advantageously be carried out by cutting, milling and / or melting. The partition walls running between adjacent first chambers are internal partition walls of the blank. The blank has external walls, which, when a web plate is used as the blank, are formed by the outer large-area plates and the external webs. The partial removal of the partition walls running between adjacent first chambers on the side facing the first side of the blank results in the outer walls of the blank on the first side of the blank protruding beyond the partition walls running between adjacent first chambers.

[0025] In step e), the first chambers are closed towards the first side of the blank while maintaining the connection of the first chambers, this preferably being done by a mechanical, chemical and / or thermal process, in particular by welding, melting and / or gluing.

[0026] In particular, by closing the blank, the outer walls of the blank are connected to one another on the first side of the blank in such a way that the blank is completely closed to the outside on the first side. By previously partially removing the partition walls running between adjacent first chambers on the side facing the first side of the blank, the first chambers are connected to one another on the first side of the blank after carrying out step c), wherein the connection exists at the points at which the partition walls were removed in step b). In step d), the first chambers are filled with a phase change material, wherein for this purpose the phase change material is filled into at least one of the first chambers from the second side of the blank. For this purpose, the blank is preferably arranged so that the second side of the blank is on top.

[0027] In step e), the first chambers are closed towards the second side of the blank, preferably by a mechanical, chemical and / or thermal process, in particular by welding, melting and / or gluing. In particular, by closing the blank, the outer walls of the blank on the second side of the blank are connected to one another in such a way that the blank is completely closed to the outside on the second side. Preferably, in step e), the first chambers of the blank on the second side of the blank are closed in such a way that they are completely closed to the outside and are not connected to one another on the second side of the blank.

[0028] The first chambers, which are filled with the phase change material after completion of step e), thus form communicating cavities that are completely closed to the environment, whereby the cavities only communicate with each other via the connection on the first side of the blank.

[0029] Advantageously, the top side of the filled element is formed by the first side of the blank. The top side defines the arrangement of the filled element during use. In this way, the first chambers filled with phase-change material are only connected to each other at their top sides, so that if one of the first chambers is damaged, only phase-change material can escape from the damaged first chamber, but not from the other first chambers.

[0030] The connection between the first chambers advantageously makes it possible to fill the first chambers in step d) by pouring into just one of the first chambers, since the phase change material is distributed over all of the first chambers as a result of the connection. This can simplify and accelerate filling considerably. Advantageously, the phase change material can also be poured into at least one of the first chambers using overpressure, in particular with a pressure greater than 0.5 bar, in particular greater than 1 bar, in particular greater than 1.5 bar, in particular greater than 2 bar. This can accelerate filling even further. Depending on the rheological properties of the phase change material used, this procedure leads to a fill level difference of varying degrees between the chambers, when only one fill opening is used, in particular rising from the edges of the element orof the plate towards the filling opening, as is schematically illustrated by way of example in Fig. 3d. Therefore, it can advantageously be provided, in particular in order to prevent partial overflow of chambers, to seal several and / or all openings on the filling side with different contact pressure, in particular with decreasing contact pressure, from the filling chamber towards the element or plate edges, in order to prevent vortex formation and to prevent partial overflow of the plate or chambers and / or to increase the speed of the filling process. This can be achieved, for example, by a spring steel with a sealing rubber surface, which is attached to the nozzle and thus results in a contact pressure that decreases towards the plate edge, depending on the spring force of the spring steel used.

[0031] Furthermore, it can advantageously be provided to stabilize at least the lowermost region of the respective element or plate during filling by clamping the element or plate flat in order to prevent damage due to the high internal pressure during filling.

[0032] The cross-section of the chambers extending from the first to the second side of the blank of the blank provided in step a) preferably has a maximum diameter of between 2 mm and 60 mm, in particular between 6 mm and 30 mm, in particular between 8 mm and 21 mm. The maximum diameter refers in particular to the maximum distance between two points on the inside of the chamber in the cross-section. However, the diameter can also be defined, for example, as an equivalent diameter, i.e. as the diameter of a circle with the same area, or as a Feret diameter. The size of the diameter is preferably selected depending on the intended use and the material used for the blank.

[0033] It is particularly advantageous to use standard, available plastic multi-wall sheets as blanks, as they can be provided with minimal effort and cost. However, specially manufactured blanks for a specific application can also be used. The blank's manufacturing material can also be selected depending on the intended use; in addition to plastics, other materials such as metals or natural materials can also be used.

[0034] A wide variety of materials can be used as phase change materials, depending on the intended use. The melting temperature of the phase change material used can vary depending on the application. A phase change material with a melting temperature between -44 °C and +93 °C is preferred.

[0035] For this purpose, a salt hydrate mixture can advantageously be used as a phase change material, for example the so-called cryohydrate, a mixture of approximately 21 wt.% sodium chloride and 70 wt.% water. This melts at approximately -21°C and can be used for cooling purposes, although it should be noted that the melting temperature can vary during the melting process. Other salt hydrate mixtures can also advantageously be used, each having a melting temperature of, for example, 0, 15, 18, 21, 23, 25, 27, 29, 33, 36, 43, 56, 81, 89, or 91°C. Corresponding salt hydrate mixtures assigned to the specified melting temperatures are known from the literature and are therefore not listed individually. It should be noted, however, that the hydration stage influences the respective solidification temperature. For example, calcium chloride melts and solidifies as hexahydrate at 29 °C and as tetrahydrate at 36 °C., as well as dihydrate or anhydrate at even higher temperatures. In addition to salt hydrates, meltable materials such as paraffins, waxes, fatty acid esters, and other chemical reactants can also be advantageously used as phase-change materials. Suitable phase-change materials are also described, for example, in the article "Latent Heat Storage Materials and Systems: A Review," International Journal of Green Energy, 2: 1-56, 2005. In principle, all phase-change materials described in this article can be used for the process.

[0036] Most phase-change materials change their volume upon melting or solidifying; in particular, they contract upon solidification, with the exception of water, which expands upon solidification. Therefore, it is advantageous to fill less than 100%, in particular less than 95%, and in particular less than 90%, of the volume of the first chambers with phase-change material. This advantageously provides an air cushion in the first chambers, preventing deformation of the chambers during phase transitions of the phase-change material.

[0037] The above-mentioned object is also achieved by an element filled with phase change material, which element has a plurality of chambers at least partially separated from one another by at least one partition wall, wherein the chambers each extend substantially from a first side of the element to a second side of the element, and wherein the chambers comprise first chambers which are designed as cavities communicating with one another and form a common, closed cavity which is at least partially filled with phase change material.

[0038] Preferably, the first chambers of the element are connected to one another only at their upper ends to form communicating cavities, so that advantageously, in the event of damage to one of the first chambers below the connection arranged above between the first chambers, only phase change material escapes from the undamaged first chamber, but not from the undamaged first chambers.

[0039] Furthermore, the chambers of the element can advantageously comprise second chambers, each forming a closed cavity filled with a different material than the first chambers, in particular with water or air, and / or third chambers forming an open cavity. And wherein in particular the chambers are arranged in layers, wherein each layer comprises a plurality of chambers arranged next to one another substantially in one plane, the layers are arranged next to one another in a direction perpendicular to the layer planes, and adjacent layers each have a different composition of first, second and / or third chambers.

[0040] The described element can be produced in particular using the method described above.

[0041] The invention will be explained in more detail below using exemplary embodiments in conjunction with the drawings. Figure 1 shows a schematic representation of an exemplary blank usable for the method in a perspective view.

[0042] Figure 2 is a schematic plan view of the first side of the blank shown in Fig. 1,

[0043] Figure 3a is a schematic cross-sectional view of the blank shown in Fig. 1,

[0044] Figure 3b is a schematic cross-sectional view of the blank shown in Fig. 3a, in which the partition walls extending between adjacent first chambers have been partially removed on the side facing the first side of the blank,

[0045] Figure 3b' is a schematic representation of the blank shown in Fig. 3b in perspective view,

[0046] Figure 3c is a schematic cross-sectional view of the blank shown in Fig. 3b, in which the first side of the blank has been closed,

[0047] Figure 3c' is a schematic representation of the blank shown in Fig. 3c in perspective view,

[0048] Figure 3d is a schematic cross-sectional view illustrating the filling of a phase change material into the blank shown in Fig. 3c,

[0049] Figure 3e is a schematic cross-sectional view of the blank after completion of the filling process shown in Fig. 3d,

[0050] Figure 3f is a schematic cross-sectional view of the blank shown in Fig. 3e, in which the second side was closed at the end of the manufacturing process,

[0051] Figure 3g is a schematic cross-sectional view of a preferred embodiment of a phase change material filled element corresponding to that shown in Fig. 3f, in a preferred orientation for use, in which the first side of the blank forms the top side,

[0052] Figure 4 is a schematic cross-sectional view of a damaged element,

[0053] Figure 5 is a schematic representation of another exemplary blank that can be used for the process in a perspective view,

[0054] Figure 6 is a schematic representation of yet another exemplary blank that can be used for the method in a perspective view, and Figure ? is a schematic representation of another preferred embodiment of an element filled with phase change material, which comprises several layers with chambers of different designs.

[0055] Figure 1 shows a schematic representation of an exemplary blank 100 that can be used for the method in a perspective view. In the illustrated embodiment, the blank 100 is designed as a web plate comprising nine parallel chambers 101 to 109 that form hollow chambers. The blank 100 has a first side 110, which in the illustration in Fig. 1 is the front side of the blank 100, and a second side 120, which in the illustration in Fig. 1 is the rear side of the blank 100. The chambers 101 to 109 are each closed to the outside by the outer walls of the blank 100, which are arranged at the top and bottom in the illustration in Fig. 1, and the outer chambers are additionally closed by the lateral outer walls 141 and 142, respectively. Adjacent chambers of the chambers 101 to 109 are separated from one another by partition walls 130, referred to as webs in a web plate. Furthermore, the chambers 101 to 109 are open towards the first and second sides of the blank.The number of nine chambers is chosen merely as an example; in principle, any suitable number can be provided, although a significantly larger number of chambers can also be provided advantageously, for example more than 10, more than 30, more than 70 or more than 100.

[0056] Fig. 2 shows a schematic plan view of the first side 110 of the blank 100, wherein it can be seen that the chambers 101 have a square cross-sectional profile in the illustrated embodiment. The cross-sectional profile is also chosen only as an example; the chambers can advantageously also have other cross-sectional profiles, for example triangular, rectangular, hexagonal, or rounded, as shown, for example, in Figures 5 and 6. Advantageously, the cross-section of the chambers 101 to 109 extending from the first to the second side of the blank 100 can have a maximum diameter between 2 mm and 60 mm, in particular between 6 mm and 30 mm, in particular between 8 mm and 21 mm. In the illustrated embodiment, the outer walls arranged at the top and bottom in Fig. 1 have the distance 150 shown in Fig. 2.The distance 150 can be, for example, 10 mm, whereby in the example shown, the maximum diameter of the cross section of the chambers 101 to 109 is 200 mm, i.e., approximately 14 mm. Furthermore, a section line AA is drawn in Fig. 2, and the corresponding sectional view is shown in Fig. 3a. The method described above is explained in detail below by way of example in conjunction with the drawings.

[0057] In step a), the blank 100 shown in Figures 1, 2 and 3a is provided, which comprises a plurality of chambers 101 to 109, wherein adjacent chambers are each separated from one another by a partition wall 130 running between the adjacent chambers, wherein the chambers 101 to 109 each extend from a first side 110 of the blank 100 to a second side 120 of the blank 100 and the chambers 101 to 109 are open to the first and second sides of the blank 100. The chambers 101 to 109 comprise at least two first chambers to be filled with a phase change material, wherein in the illustrated embodiment the chambers 102 to 108 are first chambers to be filled with a phase change material.

[0058] In step b), the first chambers 102 to 108 are connected to one another by partially removing the partition walls 130 running between adjacent first chambers, as shown in the cross-sectional view in Fig. 3b. In the case of the machined blank 100' shown as an example in Fig. 3b, a section of the partition walls 130 on the side facing the first side 110 of the blank 100 was completely removed for the sake of simplicity. However, the partial removal of the partition walls 130 can be carried out in a variety of ways, as long as a connection is thereby created between adjacent first chambers. Suitable methods for partially removing the partition walls include, for example, cutting, milling or melting, wherein the method used is preferably selected depending on the material of the blank. For further illustration, Fig. 3b' shows a schematic perspective view of the blank 100' shown in Fig.3b shown machined blank 100'.

[0059] In step e), the first chambers 102 to 108 are closed toward the first side of the blank 100' while maintaining the connection between the first chambers 102 to 108. As explained above, this can preferably be done by a mechanical, chemical and / or thermal process, in particular by welding, melting and / or gluing. In the example shown in Fig. 3c, a material layer 210 was fused to the blank 100' on the first side 110 to form the blank 100" shown. In the illustrated embodiment, the blank 100' was completely closed to the outside on the first side 110, so that the first chambers 102 to 108, as well as the further chambers 101 and 109, are each completely closed to the first side 110. As can be seen in Fig. 3c, the connection between the first chambers 102 to 108 was maintained during closing, so that the chambers 102 to 108 form communicating cavities.For further illustration, Fig. 3c' shows a schematic perspective view of the machined blank 100 shown in Fig. 3c.

[0060] In step d), the first chambers are filled with a phase change material 200. This is shown in Fig. 3d, wherein in the illustrated embodiment, the blank 100 is first rotated by 180° for this purpose and the first chambers 102 to 108 are filled with the phase change material 200 from the second side 120. Since the first chambers 102 to 108 are connected on the side 110 facing the first side 110 of the blank, the filling of the first chambers, as shown in Fig. 3d, can be carried out particularly advantageously by filling the phase change material 200 into only one of the first chambers, in the illustrated example, the chamber 105. Advantageously, the filling of the phase change material 200 into at least one of the first chambers can be carried out with an overpressure, in particular with a pressure greater than 0.5 bar, in particular greater than 1 bar, in particular greater than 1.5 bar, especially greater than 2 bar.In this way, filling can be carried out in a particularly simple and rapid manner. The filled blank 100'" is shown schematically and as an example in Fig. 3e.

[0061] In step e), the first chambers 102 to 108 of the filled blank 100'" are closed toward the second side of the blank. This can again preferably be done by a mechanical, chemical, and / or thermal process, in particular by welding, melting, and / or gluing. In the example shown in Fig. 3f, a material layer 220 was fused to the filled blank 100'" on the second side 120 to form the filled element 300 shown. In the illustrated embodiment, the blank 100'" has been completely closed to the outside on the second side 120, so that the first chambers 102 to 108, as well as the further chambers 101 and 109, are each completely closed to the second side 120. As can be seen in Fig. 3f, the chambers 102 to 108 of the filled and closed element 300 form communicating cavities.

[0062] The element 300 shown in Fig. 3g comprises, in addition to the first chambers 102 to 108 filled with the phase-change material 200, second chambers 101 and 109, which are filled with air after completion of the manufacturing process in the illustrated embodiment. Depending on the intended use, second chambers could also be provided that are filled with a material other than air instead of the phase-change material 200.

[0063] Particularly advantageously, the first side 110 forms the upper side of the filled element 300 when the element 300 is inserted, as shown in Fig. 3g. This offers a particular advantage in the event of damage 400 to the element 300, as shown in Fig. 4. In the case of such damage 400, in which in the example shown the chamber 103 was damaged and thus opened to the outside, in the illustrated orientation of use, phase change material 200 can only escape from the damaged first chamber 103, but not from the undamaged first chambers 102 and 104 to 108. In this way, the function of the element 300 can be largely retained even in the event of damage. Advantageously, the element 300 can be provided with a usage instruction, for example with an arrow pointing in the direction of the arrow 500 shown in Fig. 3g, and an indication that the arrow indicates the upward direction.

[0064] Figures 5 and 6 show, by way of example, further advantageous embodiments of a blank 610 or 820 which can be used for the method described above.

[0065] Fig. 7 shows a further advantageous embodiment of an element 310 filled with phase change material 200, wherein in this embodiment third chambers 320 are provided which form an open cavity, wherein the chambers are arranged in layers 331 to 335, wherein each layer comprises a plurality of chambers arranged essentially next to one another in a plane, the layers are arranged next to one another in a direction perpendicular to the layer planes, and adjacent layers each have a different composition of first, second and / or third chambers.In the illustrated embodiment, for example, the layers 331, 333 and 335 each comprise only third chambers 320, while the layers 332 and 334 can be constructed, for example, analogously to the element 300 described above and can comprise both first chambers filled with a phase change material and second chambers filled with a different material, for example with air.

[0066] It should be noted that an element can of course also comprise only first chambers, for which purpose, for example, in the blank 100' shown in Fig. 3b, instead of only connecting the chambers 102 to 108, all chambers 101 to 109 can be connected to one another.

[0067] Furthermore, it should be noted again that the blanks described above or elements produced from them can have a significantly higher number of chambers than shown as examples in the figures, especially when scaled to very large elements.

[0068] Further exemplary embodiments, as well as advantages and advantageous uses of the described method for producing an element at least partially filled with phase change material, as well as a corresponding element filled with phase change material, are described below.

[0069] The process advantageously consists of several sub-steps in production, which result in a secure, filled element or container segmented to prevent leakage. Advantageously, for example, an extruded product, in particular an extruded profile, can be easily pre-finished to a desired final size, optionally with an allowance to compensate for a change in size due to subsequent processing steps. The extruded containers, for example multi-wall sheets with hollow chambers, are preferably made of thermoplastics, but can also be made of metals, thermosets, or natural materials. A particularly advantageous aspect is the creation of a connection between the chambers; for this purpose, an easy-to-implement mechanical or thermal processing of an open side of the extruded product can be carried out.The appropriately machined side can then be easily closed using different methods, for example mechanically, chemically or thermally. The element can now be rotated and filled very efficiently with a phase change material from the still open side. Filling can particularly advantageously take place via any desired filling opening, i.e. for example any of the first chambers 102 to 108 described above, wherein the filling opening is preferably completely closed by a plug or similar in order to enable pressure filling. In particular, a liquid is used as the phase change material, which liquid is then distributed throughout the entire element, the fill level being geodetically equalized. Filling can take place quickly and under pressure, since the chamber is preferably completely sealed at the rear.The entire container is preferably filled through a single filling opening, but filling can also occur through multiple filling openings. Depending on the viscosity of the liquid and the size of the connecting openings between the chambers, the filling opening must be sealed off from a filling nozzle used for filling in order to enable filling under positive pressure. A flexible rubber element, for example, can be used for this purpose. Sealing the filling side using mechanical, chemical, or thermal processes completes the manufacturing process, producing an element that ensures low-leakage storage in the event of improper damage when the machined side is positioned upwards.

[0070] It should be noted that a filling device, preferably connected to a 3-axis gantry robot, or a filling line with an adjustable nozzle or adjustable blanks can be advantageously used for filling the blanks. For uneven cross-sectional profiles of the blanks to be filled, the filling openings are preferably approached using an automated control system based on optical measurement technology or manually.

[0071] An example of an element that can be manufactured using the described process is a wall-sized, filled hollow-wall or multi-wall sheet made of thermoplastic. A 1 m wide sheet, for example, consists of approximately 90 thin-walled chambers, which ensure additional stability while maintaining a very high surface area / volume ratio. Such sheets can be advantageously produced in large quantities and at low cost. In the construction sector, an element manufactured using the described process can measure 1.2 m x 2.40 m x 0.02 m and have a surface area of ​​2.88 m. 2 and a transmission area of ​​5.76m 2 It can be inserted into partition walls or sandwich structures in just a few minutes and replaces up to 50 state-of-the-art blow molds of identical dimensions. The single-shot filling also significantly reduces production time.

[0072] The invention advantageously enables free scalability of the elements without tool changes and / or the expensive production of a blow molding tool, thus enabling economical production of small batches. The possibility of flexible production, even of large elements, enables low-labor installation and use in automated prefabricated housing and industrial applications. The invention particularly advantageously uses low-cost hollow-core panels or semi-finished products from continuous extrusion machines for the production of the elements.

[0073] A particularly advantageous feature is the simple filling process, requiring only one filling opening, yet still creating a multitude of mutually leak-proof subcompartments. This also makes it possible to repair damaged areas economically, as hardly any phase-change material escapes.

[0074] The invention advantageously enables a new method of manufacturing an element filled with phase change material, which preferably uses two-dimensional, continuously extruded semi-finished products as the basic product. In particular, the invention can advantageously provide for two-dimensionally extruded plastic strands to be produced on a large scale, cut to size in the final production, the webs on one side being removed by a few centimeters and then, for example, melted. This results in an element in which the individual chambers are connected to one another at the base. Filling can occur either through one or more openings. The connection between the chambers results in a leveling of the liquid levels. The element, ieFor example, a plate, particularly a multi-wall plate, is typically filled to 90 or 95% since phase change materials are known to contract when they solidify, with the exception of water ice, which expands. An air cushion is therefore advantageously provided to prevent deformation of the element when the temperature changes. The top side of the multi-wall plates is preferably sealed automatically, e.g. by plastic welding or another process. The direction of application is rotated by 180°, so that the connected webs are at the top. This prevents the fluids from changing chambers because the air cushion is on the top side and the webs on the underside were intact before the weld was applied.

[0075] If only one cell fails, on average, 50 cm of phase-change material will leak from a 1 cm wide chamber in a 1 m high panel, which corresponds to approximately 0.5% of the total mass. Suitable measures can be taken to repair the failure site, such as plastic adhesive or gasket-backed furniture screws.

[0076] The described process therefore advantageously achieves completely free scalability in size, and thus also marketability in small-quantity markets, response to customer requirements, adaptation of the PCM elements to non-rectangular openings, and leakage protection for 99.5% of the material.

[0077] The applications of the described elements are diverse, particularly in the field of latent heat or latent cold storage. Cold storage can be advantageous in deep-freeze systems using the aforementioned cryohydrate at -21 °C. In combination with photovoltaics and heat pumps, such a cooling system can be cooled in sunshine with a photovoltaic-powered heat pump and retains its cold temperature for several days even without additional electrical power.

[0078] Another example is filling with plain water. This allows food to be kept close to the cooling point on the Celsius scale for refrigerated transport, refrigerators, etc., to ensure maximum freshness for as long as possible.

[0079] Another application is in the building sector, where a PCM mixture that melts at a comfortable temperature is inserted as a phase-change material. The inventors have already had positive experiences at temperatures of 21 °C, 23 °C, or even 25 °C. The described element can also be used as a heat storage device, which absorbs the sun during the day, heats up, and releases the heat again at night without changing the temperature.

[0080] The high heat capacity of the described elements is crucial, especially for applications where an object has a low heat capacity. Such an application could be in greenhouses, where the described elements could be used as tables. The elements are extremely stable thanks to the internal struts. During the day, the greenhouse heats up, although less so when more elements filled with phase-change material are used. The plants in the greenhouse then experience temperatures above their melting point rather than 45 or 50°C. At night, this heat is released again, and the temperature in the greenhouse drops only slightly.

[0081] Filling the element chambers with air can also be advantageous, as in the case of chambers 101 and 109 described above. Air has a thermal conductivity of 0.028 W / (m K) when stationary. Numerical calculations show that ribs up to 20 mm deep allow virtually no air movement. With the advantageous maximum diameters of the cross-sectional profiles of the chambers described above, filling them with air therefore has almost the same effect as stagnant air. This reduces the k-value of such chambers because the heat must dissipate almost entirely via the ribs.

[0082] In addition to salt hydrates, paraffins, for example, can be used as phase-change materials. These substances have known melting points of 0, 4, 6, or 8 °C. For applications above 0 °C, subcooling during the solidification process can be tolerated, and when the described elements are used as food enclosures, the food would not suffer frost damage if the outside temperature drops below 0 °C, since the interior temperature does not fall below 0 °C.

[0083] As already explained above, the invention can also be advantageously used in house construction, especially if the building itself is a lightweight structure. House construction is a particularly advantageous area of ​​application for phase change materials, as the desired comfortable temperature here lies within a very narrow temperature variation level. The comfortable temperature of rooms is often not below 20 °C and not above 23 °C. Compared to a water storage tank, which can only increase by 3 °C, a PCM storage tank offers a considerable advantage. A comparison of a cubic meter of PCM storage and a cubic meter of water storage shows, for example, that the cubic meter of water storage can store approximately 3 kWh with a 3-degree temperature increase, whereas the PCM storage tank can store 80 kWh, also with a temperature increase of 3 °C. In the calculation example, this results in an advantage for the PCM storage tank by a factor of 80 / 3, i.e. approximately 26.

[0084] In conjunction with prefabricated houses, which are characterized by a small amount of building material and therefore have a lower CO2 footprint than solid houses, elements according to the invention can be installed, for example, between the roof rafters and prevent the penetration of heat from outside. The elements according to the invention can, however, also be installed in the interior wall area or in the floor. Air-flow elements are also conceivable, e.g. in the form of columns made of stacked panels, as shown in a simplified, schematic and exemplary manner in Fig. 7. Temperature stabilization can thus be achieved using these elements, particularly effectively on the upper floor. An element with a thickness of 1 cm theoretically replaces a concrete ceiling of almost 30 cm. The invention thus advantageously enables the realization of solutions that could not be achieved using previous methods.

[0085] The possibilities for installing the elements according to the invention are diverse, e.g., in walls, floors, but also in furniture and electronic circuits. In principle, they can be used anywhere where strong temperature stabilization is required.

[0086] Another example application is at melting points of 36–43°C in combination with aqueous slurry and as a latent heat storage device for heat pumps. Heat pumps do not allow for the intermediate storage of sensible heat in water, as the heat pump can only generate higher temperatures with very low efficiency. When using phase-change materials, the temperature always remains constant and, through the correct selection of salt hydrates, can be brought into the optimal range for the heat pump. For example, a 36°C storage device could be supplied by the heat pump with 39°C at 3°C ​​for charging. At 33°C, it can be discharged again and the heat then fed into a floor or wall heating system.

[0087] Special embodiments may also involve the use of multi-layer structures. For example, multi-wall sheets can be manufactured with, for example, five layers, i.e., in an arrangement similar to that shown in Fig. 7.

[0088] In such an arrangement, it would be advantageous to fill the individual layers with air as an insulator, and the subsequent layers with phase-change materials of varying temperature levels. This would allow for a gradual dissipation or supply of energy.

[0089] The manufacturing process of a multi-layer or multi-layered element, such as the one shown in Fig. 7, can advantageously also be carried out in segments, ie each layer or layer can be manufactured individually, e.g. individually melted with a plastic melt sheet or cast in another way, wherein the layers or layers are then joined together in a suitable manner.

Claims

Patent claims 1 . A method for producing an element (300) at least partially filled with phase change material, comprising the steps of: a) providing a blank (100) having a plurality of chambers (101-109), wherein adjacent chambers are each separated from one another by a partition wall (130) running between the adjacent chambers, wherein the chambers (101-109) extend from a first side (110) of the blank (100) to a second side (120) of the blank (100), the chambers (101-109) are open to the first and second sides of the blank (100), and the chambers (101-109) comprise at least two first chambers (102-108) to be filled with a phase change material, b) connecting the first chambers (102-108) by partially removing the partition walls (130) running between adjacent first chambers on the first side (110) of the blank (100) facing side,c) closing the first chambers (102-108) towards the first side (110) of the blank (100) while maintaining the connection of the first chambers (102-108), d) filling the first chambers (102-108) with a phase change material (200) by filling the phase change material (200) into at least one (105) of the first chambers (102-108) from the second side (120) of the blank (100), and e) closing the first chambers (102-108) towards the second side (120) of the blank (100) so that the first chambers (102-108) of the filled element (300) form communicating cavities that are completely closed to the environment.

2. The method according to claim 1, wherein the blank (100) provided in step a) is produced by means of an extrusion process, in particular by extrusion of a thermoplastic or thermosetting plastic.

3. Method according to one of the preceding claims, wherein the top side of the filled element (300) is formed by the first side (110) of the blank (100, 100', 100", 100'").

4. Method according to one of the preceding claims, wherein the chambers (101-109) comprise second chambers (101, 109) filled with a different material than the first chambers in particular with air or water, and / or third chambers (310) which are not closed to the first (110) and / or second (120) side of the blank (100).

5. Method according to one of the preceding claims, wherein the partial removal of the at least one partition wall (130) in step b) is carried out by means of cutting, milling and / or melting, and / or the closing of the first chambers (102-108) in step e) and / or in step e) is carried out by a mechanical, chemical and / or thermal process, in particular by welding, melting and / or gluing.

6. Method according to one of the preceding claims, wherein the filling of the phase change material (200) into the at least one (105) of the first chambers (102-108) takes place with an overpressure, in particular with a pressure greater than 0.5 bar, in particular greater than 1 bar, in particular greater than 1.5 bar, in particular greater than 2 bar.

7. Method according to one of the preceding claims, wherein the cross section of the chambers (101-109) extending from the first (110) to the second (120) side of the blank (100) of the blank (100) provided in step a) has a maximum diameter between 2 mm and 60 mm, in particular between 6 mm and 30 mm, in particular between 8 mm and 21 mm.

8. Method according to one of the preceding claims, wherein the chambers (101-109) extend substantially parallel to one another along an axis from the first (110) to the second (120) side of the blank (100), wherein the blank is designed in particular as a web plate, double web plate or multiple web plate.

9. Method according to one of the preceding claims, wherein less than 100%, in particular less than 95%, in particular less than 90%, of the chamber volume of the first chambers (102-108) is filled with phase change material (200).

10. Element (300, 310) filled with phase change material, in particular producible by a method according to one of claims 1 to 9, wherein - the element (300, 310) comprises a plurality of at least partially separated from each other by at least one Partition wall (130) has separate chambers (101-109, 320), wherein the chambers (101-109, 320) each extend substantially from a first side (110) of the element (300, 310) to a second side (300, 310) of the element (300, 310), and wherein - the chambers (101-109, 320) comprise first chambers (102-108) which are designed as cavities communicating with one another and form a common closed cavity which is at least partially filled with phase change material (200).

11. Element according to claim 10, wherein the first chambers (102-108) are connected to each other only at their upper ends to form communicating cavities.

12. Element according to claim 10 or 11, wherein the chambers (101-109, 320) comprise second chambers (101, 109), each forming a closed cavity filled with a different material than the first chambers, in particular with water or air, and / or third chambers (320), which form an open cavity, and wherein in particular the chambers are arranged in layers (331-335), wherein each layer comprises a plurality of chambers arranged next to one another substantially in a plane, the layers are arranged next to one another in a direction perpendicular to the layer planes, and adjacent layers each have a different composition of first, second and / or third chambers.

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